So I have a 2.5in 320gb Laptop hard drive, and a 40gb IDE drive. The 320gb is 5400RPM vs the IDE that is 7200RPM, seek times on the IDE is average 8.9MS and on the SATA its 12ms. Now is there any reason to go with one or the other, I found myself running out of space on the K6-2, and my copy of 98SE is prepatched with LBA48bit support. The other diffrence is age, the 40gb is an older WD400BD, or as I call it a Western Digital Yellow Tag drive and they seem to fail alot, though this one is still working, I dont trust it, the other is a Toshiba laptop drive.